In a turbomachine, such as a gas turbine engine, air is pressurized in a compressor then mixed with fuel and burned in a combustor to generate hot combustion gases. The hot combustion gases are expanded within the turbine section where energy is extracted to power the compressor and to produce useful work, such as powering a propeller for an aircraft in flight or turning a generator to produce electricity. The hot combustion gas travels through a series of turbine stages. A turbine stage may include a row of stationary vanes followed by a row of rotating turbine blades, where the turbine blades extract energy from the hot combustion gas for powering the compressor and providing output power.
In a multistage axial compressor, the cooperating rows of stator vanes and rotor blades defining the stages typically decrease in size to progressively pressurize air as it passes through the stages. The compressor vanes and blades comprise corresponding airfoils which typically vary in configuration as their size decreases from stage to stage for maximizing performance of the compressor.
As air flows through the compressor, the flow or pressure distribution of the air as it is being compressed through the stator vanes and rotor blades is characterized as a complex three dimensional flow field varying circumferentially around the compressor, radially along the span of the vane and blade airfoils, and axially along the circumferentially opposite pressure and suction sides of the airfoils. The performance and stability of blade airfoils is significantly affected by the aerodynamic sweep and aerodynamic dihedral of the airfoil. In particular, it is generally desirable to develop a 3-dimensional design of a blade airfoil to include forward or aft sweep, or a combination of forward and aft sweep, depending on the particular application of the blade, to improve performance and/or stability. However, prior art airfoil designs have generally not emphasized incorporating significant dihedral into airfoils, and especially have not incorporated significant dihedral in combination with sweep.